I have simple iOS App using Network.Framework, NWConnection and NWEndpoint to setup a TCP connection to a Microchip RN-171. It all worked fine until iOS 14 when I started to occasionally get this error:
[tcp] nw_proto_tcp_route_init [C1.1:1] no mtu received
at which point the connection just locks up with no further data flow in either direction is possible with respect to iOS.
I'm not well schooled in the art of Network protocols. However looking at the RN-171 data sheet I see that the default value for mtu is 1524 so I am assuming that during the negotiation between the RN-171 and iOS this value should be set and something in iOS 14 means that this value doesn't always get to iOS.
Any ideas what the root cause might be and how to fix it?